/*
 * Copyright (c) 2004-2022, University of Oslo
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the copyright holder nor the names of its contributors 
 * may be used to endorse or promote products derived from this software without
 * specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.hisp.dhis.artemis.config;

import java.util.function.Supplier;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.stereotype.Component;

/**
 * @author Luciano Fiandesio
 */
@Component
public class UsernameSupplier implements Supplier<String> {
  // TODO this may come from configuration
  private static final String DEFAULT_USERNAME = "system-process";

  public UsernameSupplier() {}

  @Override
  public String get() {
    Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
    if (authentication == null
        || !authentication.isAuthenticated()
        || authentication.getPrincipal() == null) {
      return DEFAULT_USERNAME;
    } else {
      Object principal = authentication.getPrincipal();
      if (!(principal instanceof org.springframework.security.core.userdetails.UserDetails)) {
        return DEFAULT_USERNAME;
      } else {
        org.springframework.security.core.userdetails.UserDetails userDetails =
            (org.springframework.security.core.userdetails.UserDetails)
                authentication.getPrincipal();
        return userDetails.getUsername();
      }
    }
  }
}
